FW AFD this afternoon.
.LONG TERM... /NEW/
/Saturday through Wednesday/
Saturday looks to be the warmest day for a while as continued WAA
boosts highs into the mid 60s near the Red River to the mid 70s in
Central Texas. Low level moisture will also continue to increase
across East Texas during the day prior to a strong fropa arriving
in the afternoon. Forecast soundings indicate MUCAPE up to 1000
J/Kg in our southeast counties above the stable surface layer
prior to fropa, with the main warm sector and surface
destabilization staying off to our east. This may be enough for a
strong to marginally severe storm or two with hail or wind
threats, and SPC has our southeast counties in a slight risk for
a few possible strong to severe storms. Again, however, the main
severe threat will be off to our east in the SHV cwa. Across our
western counties, RH will drop down towards 30 percent during the
day with the gusty winds expected both ahead of and behind the
front, and this combo could increase the fire danger somewhat in
our Big Country counties.
Much colder temperatures will arrive post-fropa for early next
week with lows in the 20s to low 30s on Sunday and Monday and
highs in the 40s/50s. Tuesday looks a bit warmer with highs
reaching the 50s/60s, but this warmth will be short-lived as a
powerful Arctic cold front arrives during the day. This front will
be driven by a large southward moving upper trough swinging down
out of a Canada, and an associated massive 1050+ mb surface high
pressure area over the Northern Plains. Thus some of the coldest
air we have seen all winter appears increasingly likely for mid
to late next week, with latest NBM guidance much colder than
previous runs with lows in the 10s/20s and highs only in the
20s/30s for Wednesday onward. Would not be surprised to see the
NBM trend even colder given the strength of the surface high to
our north.
In addition to the cold, 12Z models continue to indicate a
significant 70kt H5 jet streak moving across Texas could provide
enough lift for some rain on Tuesday, with the rain potentially
changing to freezing rain and/or snow Tuesday night into
Wednesday as the shallow Arctic airmass arrives then deepens with
time. Main forecast question at this extended range is how much
lift/moisture and thus QPF will occur as global models differ
significantly, with the GFS much drier than the ECMWF. These
differences continue to keep the forecast confidence low for the
end of the forecast period. However, potential for some winter
weather impacts across North and Central Texas appears to be
increasing for the middle of next week.
Shamburger